Zinc-based flow batteries receive widespread attention due to their advantages of low cost and high energy density. However, zinc dendrites are easy to appear during the charge process, pierce the membrane and thus destroy the battery, which seriously restrict its further development. In this article, MFI-type zeolite nanosheets (ns-MFIs) with high mechanical strength and hydrophobicity are in situ introduced to porous polymer membranes, which spontaneously form turnup fish-scale-like structure through the one-step phase inversion/surface segregation process. This special structure well disperses mechanical energy to provide effective protection characteristics to resist the penetration of zinc dendrites, and meanwhile promotes the uniform zinc depositions on the electrode by alleviating the water migration and accelerating zincate ion diffusion, so as to prolong the cycle life of the battery for more than 600 cycles, which is 4 times and 2.5 times longer than the commercial Nafion 212 and pristine porous polymer membrane, respectively. Moreover, the subnano size pores and high-aspect-ratio of ns-MFIs afford membranes extra ion sieving ability and transport area for the charging-balancing ions OH À to ensure superior battery performance, delivering an average coulombic efficiency (CE) of ~98.5%, voltage efficiency (VE) of ~83.2%, and energy efficiency (EE) of ~81.9% at 80 mA/cm 2 .
Molecular sieving metal–organic framework (MOF) polycrystalline membranes have great potential for ion sieving and are desirable as efficient separators for devices of energy storage such as flow battery. Herein, we report a continuous MOF‐801 polycrystalline membrane with an ultrathin polymeric assembly layer (less than 10 nm) for the vanadium flow battery (VFB). Owing to the precise sub‐nanometer sieving pores and abundant H‐bond networks in MOF‐801 frameworks, the membrane exhibited better H/V selectivity (up to 194) and conductivity (about 0.028 S/cm) than commercial Nafion‐117 membrane (H/V selectivity: ~9.5, conductivity: 0.017 S/cm). VFB results revealed that a cell with above MOF polycrystalline membrane showed high coulombic efficiency (CE: 96.1%) and excellent energy efficiency (EE: 83.2%) at 20 mA/cm2, which was much comparable to Nafion membrane. This work demonstrates that MOF polycrystalline membrane is a promising candidate as ion sieving membrane for energy technique.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.